Genetic diversity of Norway spruce [Picea abies (L.) Karst.] in Romanian Carpathians

The genetic diversity of Romanian most important coniferous tree species, the Norway spruce, was estimated by means of allozyme markers. A total of 695 adult trees sampled from eleven populations grouped in six mountainous areas in the Romanian Carpathians were analyzed. In three metapopulations (Maramures, Postavar and Parang), to evaluate the influence of altitudinal gradient on genetic diversity, samples were collected from populations located at high and low altitude. At other location (Apuseni Mountains) we compared the narrow-crown biotype (Picea abies var. columnaris) and the pyramidal crown biotype (Picea abies var. pyramidalis) and explored the genetic structure of peat bog ecotype. By analyzing 7 enzyme systems and 12 enzyme coding loci, a total of 38 allelic variants have been detected. The mean value of polymorphic loci for the six sites was 86.1%, ranging between 83.3% and 91.7% and the mean expected heterozygosity was 0.115, resulting in a moderate level of genetic diversity. The highest genetic diversity (H-e = 0.134) was found in the narrow-crown spruce population. Apuseni metapopulation showed the highest genetic diversity (H-e = 0.125), being the most valuable for conservation of genetic resources. The small value of fixation index (F-sT = 0.009) indicates a low genetic differentiation between the six sites and AMOVA test revealed a very high level of genetic diversity within population (99%). Comparative analysis of genetic parameters showed small differences between high and low altitude populations at each site, probably due to the neutral character of the markers analyzed and the effect of gene flow between gradiental populations.